The objective of the proposed project is to investigate the physical-chemical properties and the biological activities (transfer of tumor immunity) of RNA from the lymph nodes and spleens of C5731/6J mice which have rejected Sarcoma I (SaI) tumors from A/J mice. The RNA extracts transfer tumor immunity by "converting" syngeneic nonimmune C57Bl mouse spleen cells in vitro to a state of specific cell-mediated immunity as detected by the spleen cell migration-inhibition technique, developed by the Principal Investigator. The RNA will be fractionated and purified by a combination of physico-chemical techniques (ultra- centrifugation, density gradient ultracentrifugation, gel filtration & adsorption chromatography and polyacrylamide gel electrophoresis) to yield homogeneous RNA preparations with high biological activity. Indentification and quantitation of RNA during the various steps of purification will be performed primarily by the spleen cell migration- inhibition technique. In addition, it is proposed to investigate if the C57B1 mouse RNA will be capable of transferring tumor allograft immunity by passively inducing (i) an accelerated rejection of the SaI tumors in nonimmune syngeneic recipient C57B1 mice, and (ii) a rejection of SaI tumors in allogeneic recipient A/J mice.